Influence of particle irradiation on the electrical and defect properties of GaAs

[摘要] The beginning of the space-age in the 1950s led to interest in the effects of radiation onsemiconductors. The systematic investigation of defect centres in semiconductors beganin earnest over 30 years ago. In addition to defect identification, information was alsoobtained on energy-level structures and defect migration properties. When designingelectronic systems for operation in a radiation environment, ~tis imperative to know theeffect of radiation on the properties of electronic components and materials comprisingthese systems.In some instances, the effects of irradiating electronic materials can be used to obtaindesired material properties (mesa isolation, implantation, etc.). However, when electronicdevices are exposed to radiation, defects may be introduced into the material. Dependingon the application, these defects may have a detrimental effect on the performance of sucha device. For this study, the semiconductor gallium arsenide (GaAs) was used and thedefects were introduced by electrons, alpha-particles, protons, neutrons and argon sputtering. These particles were generated using radio-nuclides, a high-energy neutronsource, a 2.5 MV Van de Graaff accelerator and a sputter gun.The influence of particle irradiation on the device properties of Schottky barrier diodes(SBDs) fabricated on GaAs is presented. These device properties were monitored using avariable temperature current-voltage (I-V) and capacitance-voltage (C-V) apparatus. Inorder to have an understanding of the change in electrical properties of these contacts afterirradiation, it is necessary to characterize the radiation-induced defects. Deep leveltransient spectroscopy (DLTS) was used to characterise the defects in terms of theirDLTS signature, defect concentration, field enhanced emission, and thermodynamicproperties.

[发布机构] University of Pretoria